Injection engine



Oct.` 24, 1944. vH. FISCHER .INJECTION ENGINE 2 Smets-sheet 1 Filed May 13, 1943 'f2 LNVENTOR.

Haz/22s FZ .9c/ber A i BY l Oct. 24, 1944. H. FISCHER INJECTION ENGINE Filed May 13, 1945 2 Sheets-Sheet 2 Patented et. 4, SM

- INJECTHN ENGINE Hans Fischer, Yonkers,

Corporation, Long Island City,

tion of Delaware N. Y., assigner to Lanova N. Y., a corpora- Applcation May 13, V1943, Serial No. 486,841

1 Claim.

This invention relates-to injection engines, and has to do with engines of the supplementary chamber solid injection type, in which 'the fuel is injected mechanically and without the aid of an air blast.

In engines of the character referred to, high pressure is created in the supplementary chamber or cell, as it frequently is termed, by rapid combustion therein, with resulting ejection of a high pressure, high velocity blast therefrom into the combustion chamber to assist there in dispersion and combustion of the injected fuel, such engines beingcommonly designated energy cell engines.

'I'he present practice in engines of this type is to inject the fuel into a single combustion space overlying or opening into the cylinderv bore, through a single nozzle and generally toward and into a supplementary chamber or energy cell, or through a plurality of nozzles toward and into a plurality of more or less opposed energy cells. These engines have proved to be highly efficient in the smaller sizes having a cylinder displacement volume of 86 cubic inches or less, but are not so highly efficient in the larger sizes.

In order that an injection engine may be eflicient in operation, combustion should be completed during travel of the piston from'its inner dead center position outward through a distance corresponding to turning of the crank shaft through an angle of twenty degrees, that is, within twenty crank degrees from inner dead center position of the piston. That is equally true f( r engines having cylinders of small diameter an i for engines having cylinders of large diameter.,A

In an engine having a cylinder displacement U volume of 86 cubic inches, a piston stroke of 51/2 inches, and a piston speed of 2000 feet per minute, the time available for completion of combustion, if eicient operation is'to,be had, is .00153 second. It is possible in such an engine to have complete combustion within that short period of time, due to the fact that the volume of the compression space is sufliciently small to assure that the high turbulence created bythe blast from the energy cell will cause thorough mixing with the injected fuel of all of the available combustion supporting air, with resulting rapid combustion 'and completion thereof, within the time stated. 'I'here are a number of factors which contribute to that result. The capacity of the energy cell and the distance between the passage leading thereto and the orice of the injection nozzle, are so vrelated that the proper amount of, the injected fuel enters the cell to form -with the airtherein a fuel-air mixture which will burn extremely rapidly. That assures ejection of a high pressure, high velocity blast from the cell into the compression space, assuring completion of combus- 5 tion within the time available. This blast is a result of the pressure differential in the cell and in the combustion space or chamber, regardless of the cylinder size, and the capacity of the cell should be only that required to assure the desired results, since if it were greater than required an unnecessary amount of fuel Would be burned in the cell, reducing the efficiency of the engine, and the blast from the cell would not occur quickly enough, or at sufficiently high velocity, to assure completion of combustion within the limitedv time available, further reducing eiciencv. There is thus a more or less fixed relation between the volume of the4 combustion chamber, the volume or capacity of the energy cell space, and the distance between the port of the injection nozzle ard the passage leading to the energy cell, which must be maintained in order to assure completion of combustion within degrees crank angle and resulting maximum efiiciency of the engine. That relation can be maintained in engines having acylinder displacement volume of 86 cubic inches or less, but it cannot be maintained in engines having a cylinder displacement volume materially greater than 86 cubic inches, for reasons which will be explained.

For purposes of comparison, we will consider an engine having a cylinder displacement volume of 86 cubic inches, a 51/2 inch stroke, a piston speed of 2000 feet per minute, and an output based on a mean indicated pressure of 170 pounds per square inch; and an engine having a cylinder displacement volume of 131 cubic inches, a 5% inch piston stroke, a piston speed of'2000 feet per minute, and an output based, on 'a mean indicated pressure of 170 pounds per square inch. 'I'he amo'unt of fuel injected into the smaller engine per combustion stroke is 105 cu. mm. and the amount of fuel injected into the larger engine per combustion stroke is 161 cu. mm. The amount of fuel to beV burned in the larger engine is approximately 50% in the smaller engine, but in both engines the fuel has` to be injected and combustion completed Within the same limited time, l. e., .00153 second Also, in the larger engine the necessary amount of combustion supporting air isA corre-l spondingly greater than in the smaller engine, and the combustion chamber is of greater volume. In order to mix the lager volume of air and the greater amount of fuel and obtain complete greater than that to be burned combustion within the limited time available, in the larger combustion chamber' of the larger engine of this type having a single combustion chamber opening into the cylinder bore, it would be necessary to have a blast from the engine cell of much higher velocity than the blast ejected from vthe energy cell of the smaller engine. But that is not possible, since the velocity of the blast from .the cell is a function of the pressure differential between the cell and the combustion chamber, which is substantially the same regardless of cylinder size, and cannot be increased by increasing the capacity of the cell,l nor can the duration of the blast from the cell be increased by increasing its capacity, since a larger cell requires a larger opening for charging it with fuel. Briefly, the capacity of the cell is substantially fixed relative to the volume of the combustion chamber, as previously stated.

My invention is directed to an energyl cell engine of the character stated which will avoid the difculties above referred to with respect to engines having a cylinder displacement volume greater than 86cubic inches and which will operate at the same high. eiliciency as the smaller engines. I have found that itis possible to attain that result by dividing the injected fuel and the combustion supporting air vinto two or more portions and mixing and burningeach portion separately, but causing ignition and burning of the separate portions to occur simultaneously. More specifically, I provide a combustion space divided into a plurality of combustion chambers which remain separated from each other, so far as combustion is concerned, during the combustion period of 20 crank degrees, each combustion chamber having an energy cell, and iniect a portion of the required total amount of fuel into each of the separate combustion chambers, the volume of each `combustion chamber and related factors being so chosen as to assure completion of combustion within each chamber during the available combustion period stated. Further objects and advantages of my invention will appear from the detail description.

In'the drawings: l

Figure 1 is an axial sectional view of the upper end portion of a cylinder and cylinder head of an engine embodying my invention, with the inlet and exhaust valves shown in elevation, taken substantially on line I-I of Figure 2;

Figure 2 is a sectional view taken substantially on line 2-2 lof Figure 1;

Figure 3 is a sectional view taken substantially on line.33 of Figure 2;

Figure 4 is a view similarto Figure L'taken substantially on line 4-4 of Figure 5, showing a modified form of engine embodying my invention:

Figure 5 is a sectional view taken substantially on line 5 5 of Figure 4:

"j Figure 6 is a view similar to Figure4 1 of a second modified form of engine embodying my in-v vention; and A Figure 'I is a view similar to Figure 6 of a third modified form of engine embodying my invention.

The drawings-are'semi-diagrammatic in Achar- Vacter and isll'iowfoniy those parts of the engine *with whicli'iny invention .is directly concerned. it

being understood-that the complete engine incluges a fuel pump. injection timing means. valve ool'ingfthe engine cylinders by means nf either 'aitiuid'coolant or a gaseous coolant such as air.

i gine comprises a cylinder I0 having a head II, which may be formed integrally with the cylinder, as shown, or separately from and bolted to the cylinder, as is well known, and a piston I2 operating in the cylinder. The head II comprises two combustion chambers I3 of elliptical shape in transverse section, asshownin Figure 2, each having c. conduit I4 opening into its top and ccntrolled by an inwardly opening and outwardly closing valver I5 seating in the inner end of the conduit. .The conduits I4 define passages, one

of which may be an inlet passage for air, the corresponding valve |4 being the inlet valve, and the otherv of which may be an exhaust passage for the burned gases, the corresponding valve being the exhaust valve. When the piston I2 is inl its inner dead center position, shown in Figure 1, which is its position of maximum compression, there is but slight clearance I6 between the upper face ofthe piston and theoverlying under face of the head II, only that required for mechanical reasons.

The combustion chambers I3 are oppositely inclined to the cylinder axis, downwardly and inwardly of the cylinder, as are the valves I5, and have their inner side walls connected at their inner or lower ends by a V-shaped bridge element I1. Each of the combustion chambers I3 is provided. at the side thereof adjacent bridge element II, with a boss I8 dening an 'interior supplementary chamber or cell I9 of ovoidal shape, tapering inward. Cell I9 opens at its inner end, through a restricted orifice 20, into a funnel-shaped passage 2I which opens at its inner end into combustion chamber I3. Each of the combustion chambers I3 is also provided, at the side thereof opposite to boss I8, with-a boss 22 in which is mounted, in a suitable known manner, a fuel injection nozzle 23 of suitable known type, having a tip v24 provided with a port disposed to inject a spray of fuel into chamber 23 and across the latter into passage 2I and thence into cell I9.

The top surface of the piston I2 is in the form of a segment of a sphere and the overlying under surface of the head II is correspondingly formed, to lassure minimum clearance therebetween at IS, as above noted. vThe capacity of the cell I9 is approximately ten per cent of the total volume of that cell and the corresponding combustion chamber I3, and the distance between passage 2| and the tip 24 of injection nozzle 23 is such as assure entry of the injected fuel into cell I9 in proper amount to form with the air therein a quick burningjul-air mixture.

vDuring the compression stroke of the piston I2. the displaced air is forced into the combustion chambers I3 and through passages 2l and orices 2n into the cells I9. The pressure in each of the combustion chambers 1 3 increases as the compression stroke of the piston proceeds. but remains Vhigher in each chamber I3 than in its `associated cell I9. due to the throttling effect of nozzles 23 begins, the -two beine appropriately obe ting mechanism and many other parts well v y .in'the.art, including suitabiemeans for connected to the same iniection pump. or to properly timed individual pumps, for that purpose.

lAt aboutfrom 4 to 6 before top dead center positionpf the piston I2. the fuel in each of the combustion chambers I3 is 'ignited by the heat of compressionbut burns therein relativelyzslowly. .because the injected fuel has-not vet beenvdispersed and `thoroughly mixed with the air in chambers I3, being mixed onlywith a portion accepte o that air and forming therewith a rich slow burning mixture. Accordingly this preliminary burning of a portion of the injected iuel in the chambers I3 does not cause a material rise in Pressure therein. The injection of fuel continues until about top dead center position of the piston, at which time fuel injection is terminated. It will be understood, of course, that the 'injection of fuel may be varied somewhat, depending upon operating conditions, as is known.

At about top dead center position of piston I2, the quick burning fuel-air mixture in each of the supplementary chambers or cells I 9 is ignited, by ame propagation from chamber I3 or by increase of pressure in cell .I9 incident to pressure increase in chamber I3, or by both. I'he combustion in each cell I9 is extremely rapid and causes an abrupt rise of pressure therein to a relatively high value, which may be twice the pressure then obtaining in each combustion chamber I3. The relatively high pressure in each cell I9 causes the ejection therefrom, at about from 4 to -6 after top dead center position of piston I2, of a high pressure high velocity stream of incandescent gases, in the nature of a blast, through orice 20 and passage 2| of each of the cells I9 into its associated combustion chamber I3. That occurs while the piston I2 is substantially on the dwell of its compression stroke, ready to Start down on its working stroke, and the body of air for supporting combustion of the fuel is confined within the combustion chambers I3. The blast from each of the cells I9 causes instantaneous and thorough mixing of the unburned air and fuel in each of the combustion chambers I3," resulting in greatly accelerating the rate of combustion therein, such that the combustion of the fuel is completed before appreciable movement of the piston I2 on its working stroke has occurred. In that connection, the extent of movement of the piston from its top dead center position during movement of the engine crank shaft through an angle of 20 degrees is negligible, and for all practical purposes the position shown in Figure l. In that position of piston I2, the space between the upper face thereof and the under face of the areas of head II surrounding the combustion chambers I3 is slight, such that the cooling eect of the opposed metal walls will quench any flames tending to pass from one combustion chamber I3 to the other. Consequently, mixing together of the fuel and the airl in each combustion chamber, and combustion of the resultant mixture, occurs and proceeds to completion independently of the mixing and combustion occurring in the other chamber, though both proceed simultaneously since the fuel in each is ignited by the compression of the charge by the piston. After completion of combustion, the piston is driven outward in its working stroke by expansion of the hot products of combustion. as is known.

ABy separating the total amount of fuel injected piston then occupies its per combustion stroke into a plurality of portions, and mixing each portion of the fuelwith its proportionate-amount of combustion supporting air, and then burning each portion of the fuel-air mixture separately until combustion thereof has been completed, I provide a novel method of operation which renders possible eilicient and high speed operation of solid injection energy cell engines of much larger sizes than can be operated at high eciency when a single combustion chamber is used. While my invention is particularly suited to larger engines of the character referred to, having a cylinder displacement volume in excess of 86 cubic inches, it is not limited to such larger engines since, in certain cases,

it may be used to advantage in smaller engines.

The energy cell I9 of each of the combustion chambers It, together with its orifice 2li and passage 2i, preferably is inclined downward and inward of the cylinder, as shown in Figure 3. That avoids direct impingement of the blast from cell I9 on the tip 2@ of nozzle 23 and objectionable heating thereof, and is desirable in certain cases. While I usually prefer to arrange the energy cell i9 as stated, that is not essential to my invention, and it may be otherwise suitably disposed. It will also be understood that the injection nozzles 23 may be separate structures, or may be parts of the same nozzle structure providing for separate injection into each of the combustion chambers I3 of the proper proportionate part of the total amount of fuel injected per combustion stroke of the piston. Also, under certain conditions, as when operating under light load 0r idling, one or more of the injection nozzles, if more than two combustion chambers be provided, may be disabled in any suitable known manner. In that connection, it is to be understood that I contemplate providing any suitable number of combustion chambers, each withy its associated injection nozzle and energy cell, as conditions may require, and have shown but two combustion chambers by Way of example and to explain the principle of my invention. Also, my invention comprehends two cycle engines `as well as four cycle engines.

In the modied form of engine shown in Figures 4 and 5, combustion chambers I3a are of circular cross-section and the axes thereof are parallel with the cylinder axis, as are the axes of the valves I5, the inner side walls of combustion chambers I3a are joined by a bridgeelement I'Ia of substantially uniform cross-section, and the energy' cells I9 and the injection nozzles 23 are disposed at the outer sides of the combustion chambers i311. Otherwise, the engine of Figures i and 5 is similar to that of Figures 1 to 3, inclusive, and further description thereof here is not necessary.

The modied form of engine shown in Figure 6 has a piston Ia provided on its upper or inner end with two projections I2b disposed to extend into the inner portions of combustion chambers I3b, when piston I2a, is in its top dead center position shown. In that position of piston Iza, the inner' side portions of projections i221 are spaced from the lateral surfaces of the inner side Walls of combustion chambers I2a and bridge element I'Ib, connecting the inner ends of those Walls, the minimum distance required for mechanical reasons, providing restricted clearance Ita between such surfaces. The engine of Figure 6 is otherwise slmilarto that of Figures 1 to 3, inclusive, and need not be described in greater detail here.

In the modified engine shown in Figure 7, the piston I2C is flat at its upperend except for the provision of two projections I2d disposed to enter the lower or inner portions of combustion chambers I3a, when the piston is in its top dead center position shown.y In that position of piston I 2c the inner sides of projections IZd are spaced from the lateral surfaces of a bridge element I'Ic, constituting the major portion of the inner'side walls tween the topof the piston |24: and the overlying areas of the head I la surrounding the com- A bustion chambers, is the minimum required for departing from the field and scope of my invention, and I intend to include all such variations, as fall within the scope of the appended claim, in this application in which the preferred forms 4 only of my invention have been disclosed.

' I claim:

In an injection engine of the compression ignition type. a cylinder and a piston operating therein, a head overlying 4said cylinder, an imperl'orate wall element projecting inwardly from 'said head and dening with the peripheral wall of the head a plurality of separate combustion chambers, supplementaryv chambers respectively opening into said combustion chambers through a restricted orice and a funnel like passage daring from said orice toward the associated combustion chamber, and injection means for said combustion chambers having a port opening into each thereof disposed to inject fuel thereacross into the e of thevassociated supplementary chamber, the distance between the respective ports and passages being such as to assure entry of the injected fuel into each supple` mentary chamber in proper amount to form with the air therein a quick burning fuel-air mixture elective for producing within said supplementary chamber incident to combustion therein relative high pressure effective for electing therefrom a high-pressure, high-velocity blast of gases through said drilce and passage; the volume o'f each combustion chamber being such that the blast ejected thereinto from its associated supplementary chamber effects substantially instanvtaneous and'thorough mixing together of substantially all of the unburned fuel and unconsumed air therein with resultant completion of combustion while the piston remains substantially on the dwell of its working stroke, said imperforate wall element of the head extending inwardly to cooperate with the piston lhead whereby at the inner deadcenter pomtion of the piston there is substantially no clearance between the piston head and said imperforate wall element thereby preventing combustion passing from one chamber to another thereof so that combustion in each of said chambers is substantially completed independently of combustion in the remainder thereof while the piston is on the dwell or its working stroke.

HANS FISCHER. 

